I according to the book of the concept of the so-called cascade deletion tried many times, is unable to cascade deletion, including the model and table, next to the cascade will appear grammar mistakes, the solution can only be step by step, such as TRICT delete mode table first, and then you can delete the pattern, the same is true with other, at the back of the book has no RESTRICT SQL sever and cascade options, later found to be careless, say so many, the original book that last sentence is one of the most important,